Recently, many advances have been made in modular input/output panel constructions for providing programmable controllers. These advances have typically centered upon increased maneuverability, accessibility, insertibility, and removability of input/output modules and their interconnectibility with external equipment wiring. However, in order to provide this input/output module flexibility, expensive interfacing, interconnecting, and supporting equipment is required.
In particular, these typical prior art systems all require a backplane housing into which the module is interconnected in order to provide the communication between the input/output module and the central processing unit. In addition, the module is also supportingly maintained in a housing or rack system to assure that it is maintained securely in position. Furthermore, such constructions leave obvious, aestetically unpleasing void zones if fewer modules are required than the maximum module capability of the controller.
Furthermore, external equipment wiring must be made either directly to the module or, alternatively, to an interfacing terminal connector block to which the module may be engaged or disengaged, as so desired. Typical systems which exemplify this prior art are found in U.S. Pat. No. 3,942,077 of Howard A. Powers, and U.S. Pat. No. 4,215,386 of Jay M. Prager et al.
Although these prior art systems efficiently attain their desired goals, the increased cost of manufacture for the various component parts required in these systems has prevented some potential users from being able to incorporate these systems due to their inherent initial costs. As a result, these potential users who would otherwise benefit from the systems' capabilities have been required to forego the advantages that might otherwise be enjoyed by employing a programmable controller.
Consequently, it is a principal object of this invention to provide an input/output assembly for a programmable controller which incorporates a lightweight, easily handled, readily expandable, input/output module which eliminates necessity for expensive associated support equipment and achieves an input/output system comparatively inexpensive to prior art input/output systems.
Another object of this invention is to provide an input/output assembly for a programmable controller having the characteristic features defined above wherein the input/output modules are quickly and easily securely mountingly engaged to adjacent input/output modules in order to allow the user to expand the system as expansion becomes required, without detracting from the system's performance or appearance.
Another object of the present invention is to provide an input/output assembly for programmable controller having the characteristic features defined above which also provides for quick and easy interconnection of external device wiring directly to the desired module.
A further object of this invention is to provide an input/output assembly for a programmable controller having the characteristic features defined above which is capable of rapid assembly and disassembly without requiring soldering, thereby assuring easy and reliable field maintenance while also being reliable and reasonably priced.
Another object of this invention is to provide an input/output assembly for a programmable controller having the characteristic features defined above which is quickly and easily expanded by simply assembling and interconnecting additional input/output modules to the existing input/output module up to the maximum capability of the central processor.
Other and more specific objects will in part be obvious and will in part appear hereinafter.